KR102362050B1 - Prepreg Laminate, Fiber Reinforced Composite Material, and Method for Manufacturing Fiber Reinforced Composite Material - Google Patents

Abstract

An object of the present invention is to provide a fiber-reinforced composite material having an excellent design surface, a method for manufacturing a fiber-reinforced composite material, and a prepreg laminate suitably used therefor. The present invention includes at least a prepreg [a] impregnated with a reinforcing fiber with a resin and a base material [b] not impregnated with a resin, wherein at least two prepreg [a] of the prepreg [a] are successively laminated It is a prepreg laminate comprising a structure in which both sides of the substrate [b] are sandwiched with the prepreg [a].

Description

Prepreg Laminate, Fiber Reinforced Composite Material, and Method for Manufacturing Fiber Reinforced Composite Material

The present invention relates to a fiber-reinforced composite material, a method for producing a fiber-reinforced composite material, and a prepreg laminate suitably used therefor.

Fiber-reinforced composite materials are useful in that they are excellent in strength, rigidity, conductivity, and the like. It is widely deployed in aircraft structural members, windmill blades, automobile exterior materials, automobile interior materials, and computer applications such as IC trays and notebook computer casings, and the demand is increasing year by year.

The fiber-reinforced composite material is, for example, a material formed by molding a prepreg containing a reinforcing fiber and a resin as essential components. When this material is used, it is known that pinholes and voids are generated on the surface of the fiber-reinforced composite material obtained when air or volatile components remain in the resin portion of the prepreg before or during molding. Therefore, various techniques have been proposed for the purpose of reducing pinholes and internal voids on the surface of the fiber-reinforced composite material obtained from the prepreg.

As one of them, it has been proposed to form a prepreg laminate by interposing a base material not impregnated with resin between prepreg layers in which reinforcing fibers are impregnated with resin. For example, a technique for imparting a fiber-reinforced composite material by press-molding an SMC (Sheet Molding Compound) molding material and a nonwoven fabric not impregnated with a resin has been proposed (see Patent Document 1). As another one, the technique of the fiber-reinforced resin molded article formed by laminating|stacking the fiber mat which is not impregnated with resin between the materials of the prepreg which made the reinforcing fiber impregnated with resin, such as polypropylene, is proposed (refer patent document 2).

In these techniques, the bending of fibers due to fluidity was suppressed, and as a result, it was possible to suppress the occurrence of irregularities on the surface of the SMC molded article. As a result, the peel strength of the fiber-reinforced composite material could be improved by smoothing the surface of the fiber-reinforced composite material and eliminating a layer of only the resin during lamination molding, and strengthening the interlayers in strength. However, even if the design was performed on the surface of the fiber-reinforced composite material, the desired design could not be obtained. Hereinafter, the surface of the fiber-reinforced composite material to which the design is applied is referred to as a design surface.

Japanese Patent Laid-Open No. 2008-246981 Japanese Patent Laid-Open No. 5-269909

An object of the present invention is to provide a carbon fiber reinforced composite material having an excellent design surface.

In order for this invention to achieve the said objective, this invention discloses the following aspects.

First, the following invention is disclosed as a prepreg laminated body.

(1) including a prepreg [a] in which the resin is impregnated in the reinforcing fibers and a base [b] in which the resin is not impregnated,

Among the prepregs [a], the prepreg [a] has a structure in which at least two sheets are continuously stacked,

and a structure in which both sides of the substrate [b] are sandwiched with the prepreg [a].

In addition, there exist the following as a preferable aspect of the said invention.

(2) The prepreg laminate in which at least one surface of the prepreg laminate is a design surface, and the substrate [b] is laminated on the second or third layer from the design surface side.

(3) At least one surface of the prepreg laminate is a design surface, and the prepreg [a], the base material [b], and two or more prepregs [a] are successively laminated in order from the outermost layer on the design surface side The prepreg laminate of any of the above, having a structure in which

(4) The prepreg laminate according to any of the above, wherein the base material [b] has a weight per unit area of 5 to 100 g/m 2 .

(5) The prepreg laminate according to any of the above, wherein the thickness of the base [b] is 0.1 to 1.5 mm.

(6) The prepreg laminate according to any of the above, wherein the base [b] contains carbon fibers or glass fibers, and the fibers are discontinuous.

(7) The prepreg laminate according to any of the above, wherein the thickness of the prepreg structure [a1] defined below is 0.2 to 9 times the thickness of one sheet of the prepreg [a2] defined below.

Prepreg structure [a1]: A structure comprising the prepreg [a] laminated on one side of the base material [b], in which two or more sheets of the prepreg [a] are successively laminated

Prepreg [a2]: Prepreg [a] laminated on the other side of the substrate [b] (however, when the prepreg [a] is laminated, a laminate of prepreg [a])

(8) The prepreg laminate according to any of the above, wherein the thickness of the substrate [b] is 0.1 to 3.0 times the thickness of the prepreg structure [a1] defined below.

Prepreg structure [a1]: A structure comprising the prepreg [a] laminated on one side of the base material [b], in which two or more sheets of the prepreg [a] are successively laminated

And the following invention is disclosed as a fiber reinforced composite material.

(9) A fiber-reinforced composite material using the prepreg laminate of any of the above, wherein the fiber volume content of the fiber-reinforced composite material layer [A] derived from the prepreg [a] is VfA, derived from the base [b] A fiber-reinforced composite material having a relationship of VfA>VfB when the fiber volume content of the fiber-reinforced composite material layer [B] is VfB.

And there exist the following things as a preferable aspect of the said invention.

(10) The fiber-reinforced composite material layer [B] contains a resin, and the impregnated resin is the resin impregnated in the prepreg [a].

(11) The fiber-reinforced composite material of any of the above, wherein the fiber volume content of the fiber-reinforced composite material layer [B] is 40% or less.

(12) The fiber-reinforced composite material of any of the above, wherein the fiber volume content of the fiber-reinforced composite material layer [A] present on both sides of the fiber-reinforced composite material layer [B] is 55% or more, respectively.

(13) The fiber-reinforced composite material of any of the above, wherein the void content of the fiber-reinforced composite material layer [B] is higher than that of the fiber-reinforced composite material layer [A].

(14) Fiber reinforcement of any of the above, in which the voids contained in the fiber-reinforced composite material layer [B] are distributed in 80 to 100% in the central portion of the cut surface in the cut plane along the lamination direction of the prepreg laminate composite material.

Moreover, this invention discloses the manufacturing method of the following fiber reinforced composite material.

(15) A method for producing a fiber-reinforced composite material, comprising a step of molding the prepreg laminate according to any of the above by heating and pressing.

Preferred embodiments of the method for producing a fiber-reinforced composite material include the following.

(16) The manufacturing method of the said fiber-reinforced composite material which further includes the process of performing at the pressure of -80 kPa or less (gauge pressure) in the said shaping|molding process.

(17) The method for producing a fiber-reinforced composite material according to any of the above, wherein in the heating and pressurizing step, the resin contained in the prepreg [a] is impregnated into the base material [b].

According to the present invention, a fiber-reinforced composite material having an excellent design surface is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the prepreg laminated body which concerns on one Embodiment to this invention.
2 is a schematic diagram of a prepreg laminate according to another embodiment of the present invention.
3 is a schematic diagram of a prepreg laminate according to another embodiment of the present invention.
4 is a schematic diagram of a prepreg laminate according to another embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment is demonstrated using drawings. In addition, this invention is not limited at all to drawings or an Example.

The prepreg laminate according to the present invention is a prepreg laminate comprising two or more prepregs [a] in which a resin is impregnated into reinforcing fibers and one or more substrates [b] in which no resin is impregnated. And the laminate has a structure in which at least two prepregs [a] in which resin is impregnated into reinforcing fibers are continuously laminated, and includes a structure in which both sides of the substrate [b] are sandwiched with the prepregs [a].

In the prepreg laminate 10 shown in FIG. 1 , the prepreg [a] is disposed on both sides of the substrate [b] (3), and the substrate [b] (3) is sandwiched. Above the substrate [b] (3) are the prepreg [a] (2a2) and the prepreg [a] (2a1) thereon. In the case of such an adjacent arrangement, it can be said "continuously". In addition, there is a prepreg [a] (2b1) under the base material [b] (3). The surface of the prepreg [a] (2b1) is the design surface (1).

When the prepreg laminate 10 is compression molded by a press or the like, the resin impregnated in the prepreg [a] moves to the base material [b] (3), and the fibers contained in the base material [b] (3) impregnated in between. Since the prepreg [a] (2a1) and the prepreg [a] (2a2) are laminated continuously in two layers, when the fiber reinforced composite material is manufactured by heating and pressurization, the base [a] from these prepreg [a] b] The resin impregnated with (3), and on the other hand, the prepreg [a] (2b1) having a design surface, together with the resin contained in the prepreg [a], air and volatile components contained in the base [b] ] By moving to (3), a fiber-reinforced composite material having an excellent design surface (1) can be obtained.

The prepreg [a] used in the present invention contains at least a reinforcing fiber and a resin.

Although there is no restriction|limiting in particular as a reinforcing fiber used for prepreg [a], The following are mentioned.

metal fibers such as aluminum fibers, brass fibers, and stainless fibers;

carbon fibers of PAN-based carbon fibers, rayon-based carbon fibers, lignin-based carbon fibers, and pitch-based carbon fibers;

graphite fiber; glass fiber;

organic fibers such as aramid fibers, PBO fibers, polyphenylene sulfide fibers, polyester fibers, acrylic fibers, nylon fibers, and polyethylene fibers;

Inorganic fibers such as silicon carbide fibers and silicon nitride fibers.

Moreover, the thing by which the surface treatment is given to these fibers may be sufficient. The surface treatment includes, in addition to the metal deposition treatment as a conductor, a treatment with a coupling agent, a treatment with a sizing agent, a treatment with a binder, a treatment with an additive, and the like.

These reinforcing fibers may be used individually by 1 type, and may use 2 or more types together. Among them, carbon fibers such as PAN-based carbon fibers, pitch-based carbon fibers, and rayon-based carbon fibers excellent in specific strength and specific rigidity are preferably used from the viewpoint of the weight reduction effect.

Moreover, from a viewpoint of improving the economical efficiency of the laminated body obtained, comparatively cheap glass fiber is used preferably. In particular, it is preferable to use carbon fiber and glass fiber together from the balance of mechanical properties and economical efficiency.

In addition, from the viewpoint of increasing the impact absorption of the obtained fiber-reinforced composite material and the shapeability of the laminate, aramid fibers are also preferably used, and in particular, it is preferable to use carbon fibers and aramid fibers together from the balance of mechanical properties and shock absorption.

Moreover, from a viewpoint of improving the electroconductivity of the fiber reinforced composite material obtained, the reinforcing fiber which coat|covered metals, such as nickel, copper, and ytterbium, can also be used. Among them, PAN-based carbon fibers having excellent mechanical properties such as strength and elastic modulus can be more preferably used.

As for the form of the reinforcing fibers, continuous or discontinuous forms are irrespective of the form. As long as it is in a continuous form, its arrangement is irrelevant. In order to obtain a fiber-reinforced composite material that is only lightweight and has a higher level of durability, it is preferable that the reinforcing fibers are in the form of continuous fibers such as long fibers, woven fabrics, toe and rovings arranged in one direction.

As the structure of the woven fabric, plain weave, twill weave, weaving weave, etc. are mentioned.

If it is a discontinuous type thing, as a fiber length, the reinforcing fiber of less than 15 mm is preferable from a viewpoint from which kneading|mixing becomes easy as a filler.

In addition, there is no restriction|limiting in particular as resin used for prepreg [a], For example, a thermosetting resin and a thermoplastic resin are mentioned.

As the thermosetting resin, a thermosetting resin such as an epoxy resin, a phenol resin, a vinyl ester resin, a benzoxazine resin, a polyimide resin, an oxetane resin, a maleimide resin, an unsaturated polyester resin, a urea resin, a melamine resin, etc. is preferably used. can These may apply resin etc. which blended 2 or more types. Among these, an epoxy resin, a phenol resin, and a vinyl ester resin are preferable from a viewpoint of the mechanical characteristic of a laminated body, and heat resistance. In particular, an epoxy resin is more preferable from a viewpoint of handleability in addition to the mechanical characteristic of a laminated body, and heat resistance. Since the epoxy resin exhibits the excellent mechanical properties, it is preferable to be contained as a main component of the resin to be used, and, specifically, it is preferable to contain 60 mass % or more per resin composition.

As for the epoxy resin, an epoxy resin using amines, phenols, or a compound having a carbon-carbon double bond as a precursor is preferably used.

As the curing agent for the epoxy resin, any compound having an active group capable of reacting with an epoxy group can be used. As the curing agent, a compound having an amino group, an acid anhydride group and an azide group is suitable. Examples of the curing agent include dicyandiamide, diaminodiphenylmethane and various isomers of diaminodiphenylsulfone, aminobenzoic acid esters, various acid anhydrides, phenol novolak resins, cresol novolak resins, polyphenol compounds, imidazoles. Derivatives, aliphatic amines, tetramethylguanidine, thiourea addition amines, carboxylic acid anhydrides such as methylhexahydrophthalic anhydride, carboxylic acid hydrazide, carboxylic acid amide, polymercaptan and Lewis acids such as boron trifluorideethylamine complex complexes and the like. These hardening|curing agents may be used independently and may be used together.

By using aromatic diamine as a hardening|curing agent, cured resin with favorable heat resistance is obtained. In particular, various isomers of diaminodiphenylsulfone are most suitable for obtaining a cured resin having good heat resistance. Although it is preferable to add the addition amount of aromatic diamine as a hardening|curing agent so that it may become stoichiometrically equivalent, in some cases, by setting it as an equivalent ratio of 0.7-0.8 vicinity, for example, a cured resin with a high modulus of elasticity is obtained.

In addition, by using a combination of dicyandiamide and a urea compound, for example, 3,4-dichlorophenyl-1,1-dimethylurea, or imidazole as a curing agent, high heat and water resistance is obtained while curing at a relatively low temperature. lose Curing using an acid anhydride gives a cured resin having a low water absorption compared to curing of an amine compound. In addition, those in which these curing agents are latent, for example, microencapsulated can be used.

Among the curing agents for epoxy resins, a combination of dicyandiamide and a urea compound is preferably used because it can be cured within 10 minutes at a temperature of 145°C or higher.

Moreover, it is not limited to the composition only of these epoxy resins and a hardening|curing agent, and water in which they were pre-reacted can also be mix|blended in the composition. This method may be effective for viscosity control or storage stability improvement.

It is also suitable to melt|dissolve and use a thermoplastic resin in the said thermosetting resin. As such a thermoplastic resin, in general, a bond selected from a carbon-carbon bond, an amide bond, an imide bond, an ester bond, an ether bond, a carbonate bond, a urethane bond, a thioether bond, a sulfone bond and a carbonyl bond to a main chain. It is preferable that it is a thermoplastic resin which has.

There is no problem even if it has a partially crosslinked structure. In addition, any of crystalline and amorphous may be used. Examples of resins soluble in thermosetting resins include polyamide resins, polycarbonate resins, polyacetal resins, polyphenylene oxide resins, polyphenylene sulfide resins, polyarylate resins, polyester resins, polyamideimide resins, Polyimide resin, polyetherimide resin, polyimide resin having a phenyltrimethylindane structure, polysulfone resin, polyethersulfone resin, polyetherketone resin, polyetheretherketone resin, polyaramid resin, polyethernitrile resin and polybenz imidazole resin.

The following are mentioned as a thermoplastic resin.

polyolefin resins such as polyethylene resin, polypropylene resin, and polybutylene resin;

polyester resins such as polyethylene terephthalate resin, polybutylene terephthalate resin, polytrimethylene terephthalate resin, polyethylene naphthalate resin, and liquid crystal polyester;

polyamide resin, polyoxymethylene resin; polyarylene sulfide resins such as polyphenylene sulfide resin; polyketone resin, polyetherketone resin, polyetheretherketone resin, polyetherketoneketone resin, polyethernitrile resin; crystalline resins such as fluorine-based resins such as polytetrafluoroethylene resins and liquid crystal polymer resins;

Polystyrene resin, polycarbonate resin, polymethyl methacrylate resin, polyvinyl chloride resin, polyphenylene ether resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, amorphous resins such as polyarylate resins;

Thermoplastic elastomers such as phenolic resins, phenoxy resins, polystyrene resins, polyolefin resins, polyurethane resins, polyester resins, polyamide resins, polybutadiene resins, polyisoprene resins, fluorine resins, and polyacrylonitrile resins, etc.

In addition, a thermoplastic resin selected from copolymers or modified products thereof.

Especially, from a viewpoint of the light weight of the laminated body obtained, a polyolefin resin is preferable, a polyamide resin is preferable from a viewpoint of intensity|strength, and a viewpoint of a surface external appearance uses a polyester resin preferably.

The resin impregnated into the prepreg [a] may contain an impact resistance improving agent such as an elastomer or a rubber component, and other fillers and additives within the scope not impairing the object of the present invention. Examples of these include inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration dampers, antibacterial agents, insect repellents, deodorants, color inhibitors, heat stabilizers, mold release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, A dye, a foaming agent, a foaming agent, or a coupling agent is mentioned.

In addition, it may include a filler. Examples of the filler include calcium carbonate, talc, silica, clay, glass flake, catechin, zeolite, silica balloon, glass balloon, shirasu balloon, carbon black, carbon nanotube, fullerene, graphite, metal powder, metal foil, ferrite material, alumina, titanic acid. Barium, lead zirconate titanate, barium sulfate, titanium oxide, glass beads, alumina, antimony oxide, hydrotalcite, red phosphorus, zinc carbonate, calcium oxide, etc. are mentioned. Among them, an intermediate substrate including continuous reinforcing fibers is preferable from the viewpoint of moldability.

It is preferable that the base material [b] used for a prepreg laminated body contains a fiber from the point of being easy to be impregnated with resin at the time of shaping|molding.

Examples of the fibers that can be used for the base [b] include the following.

metal fibers such as aluminum fibers, brass fibers, and stainless fibers;

carbon fibers of PAN-based carbon fibers, rayon-based carbon fibers, lignin-based carbon fibers, and pitch-based carbon fibers; graphite fiber, glass fiber;

organic fibers such as aramid fibers, PBO fibers, polyphenylene sulfide fibers, polyester fibers, acrylic fibers, nylon fibers, and polyethylene fibers;

Inorganic fibers such as silicon carbide fibers and silicon nitride fibers.

Moreover, the thing by which the surface treatment is given to these fibers may be sufficient. The surface treatment includes, in addition to the metal deposition treatment as a conductor, a treatment with a coupling agent, a treatment with a sizing agent, a treatment with a binder, a treatment with an additive, and the like. In addition, these reinforcing fibers may be used individually by 1 type, and may use 2 or more types together. Among them, carbon fibers such as PAN-based carbon fibers, pitch-based carbon fibers, and rayon-based carbon fibers excellent in specific strength and specific rigidity are preferably used from the viewpoint of the weight reduction effect.

Moreover, from a viewpoint of improving the economical efficiency of the prepreg laminated body obtained, comparatively cheap glass fiber is used preferably and it is especially preferable to use carbon fiber and glass fiber together from the balance of a mechanical characteristic and economical efficiency.

In addition, from the viewpoint of improving the impact absorption of the obtained fiber-reinforced composite material and the shapeability of the laminate, aramid fibers are preferably used. Moreover, it is preferable to use carbon fiber and aramid fiber together from the balance of mechanical characteristics and shock absorption. Moreover, from a viewpoint of improving the electroconductivity of the fiber reinforced composite material obtained, the reinforcing fiber which coat|covered metals, such as nickel, copper, and ytterbium, can also be used. Among them, PAN-based carbon fibers having excellent mechanical properties such as strength and elastic modulus, and glass fibers can be more preferably used from the viewpoint of improving the economic efficiency of the resulting laminate.

The base material [b] should just not be impregnated with resin, and as a form, a nonwoven fabric, a woven fabric, a knitted fabric, and a mat are mentioned, for example.

As the structure of the woven fabric, plain weave, twill weave, weaving weave, etc. are mentioned.

It is preferable that the base material [b] contains carbon fiber or glass fiber. It is also preferred that the fibers are discontinuous. It is possible to obtain a fiber-reinforced composite material excellent in strength and elastic modulus in a substrate including carbon fibers, and excellent in economic efficiency in a substrate including glass fibers. If the fiber is a discontinuous base material, since the thickness of the base material can be adjusted in a large or small range, the thickness of the fiber-reinforced composite material obtained can be adjusted, which is preferable.

In addition, in the prepreg laminate, at least one surface of the prepreg laminate is the design surface 1, and the prepreg [a] is laminated up to the outermost layer and the second or third layer on the design surface 1 side. This is preferable in that pinholes on the design surface of the obtained fiber-reinforced composite material are suppressed.

As shown in Figs. 1 and 2, the prepregs [a] (2b1) from the design surface 1, followed by the base material [b] (3) are provided as a prepreg laminate 10, whereby the design surface ( 1) The air and volatile components of the prepreg [a] (2b1) are impregnated and transferred to the base material [b] (3) together with the resin. As a result, an excellent design surface of the fiber-reinforced composite material is obtained. That is, the prepreg laminate has a structure in which at least one surface becomes a design surface, and two or more sheets of prepreg [a], base material [b], and prepreg [a] are successively laminated in order from the design surface side. It is preferable that they are arranged in this order from the viewpoint of suppressing pinholes on the design surface of the obtained fiber-reinforced composite material.

3 and 4 will be referred to. The prepreg [a] (2b2) and the prepreg [a] (2b1) are arranged in order from the design surface, so that the prepreg [a] becomes two layers. Moreover, it can be set as the prepreg laminated body 10 by arrange|positioning the base material [b] (3) on the prepreg [a] (2b1). Since the lamination process is not complicated, and air and volatile components in the prepreg [a] (2b1) giving the design surface 1 are leached into the base material [b] (3) together with the resin, the fiber-reinforced composite material It is preferable from the viewpoint of obtaining the excellent design surface (1) of

Further, as shown in Fig. 4, the prepreg [a] (2a2) and the prepreg [a] (2a1) are further laminated in order on the substrate [b] (3), so that the entire prepreg [a] is The prepreg laminate 10 with many laminated|stacks is also a preferable aspect. In the prepreg laminate 10 of FIG. 4 , the prepreg [a] (2a2) and the prepreg [a] (2a1) are sequentially disposed on one side of the base material [b] (3), and the prepreg [a] (2a1) is sequentially disposed on one side It has a structure in which the leg [a] (2b1) and the prepreg [a] (2b2) are arranged.

Moreover, it is preferable that the weight per unit area of the base material [b] used for a prepreg laminated body is 5-100 g/m<2>. Thereby, both the improvement of the moldability of a prepreg laminated body and the designability of a fiber reinforced composite material can be aimed at. More preferably, it is 5-80 g/m<2>, More preferably, it is 5-50 g/m<2>, Furthermore, it is 5-35 g/m<2>.

When the weight per unit area is small, there may be many pinholes on the design surface of the fiber-reinforced composite material obtained, and when it is larger than 100 g/m, the impregnation of the resin under molding into the substrate [b] becomes insufficient. In some cases, problems arise with the mechanical properties.

Moreover, it is preferable that the thickness of the base material [b] contained in the prepreg laminated body of this invention exists in the range of 0.1-1.5 mm. Thereby, the impregnation of the resin into the base material [b] and the designability of the fiber-reinforced composite material can be achieved. More preferably, it is 0.1-1 mm, More preferably, it is 0.1-0.5 mm. When the thickness is less than 0.1 mm, pinholes may increase on the design surface of the obtained fiber-reinforced composite material, and when it exceeds 1.5 mm, a problem may arise in the mechanical properties of the obtained fiber-reinforced composite material.

In the prepreg laminate, it is preferable that the thickness of the prepreg structure [a1] defined below is 0.2 to 9 times the thickness of one sheet of the prepreg [a2] defined below.

Prepreg structure [a1]: A structure comprising the prepreg [a] laminated on one surface of the base material [b], wherein two or more sheets of the prepreg [a] are successively laminated.

Prepreg [a2]: A prepreg [a] laminated on the other side of the base material [b] (however, when the prepreg [a] is laminated, a laminate of the prepreg [a]).

This thickness ratio enables both the impregnation into the base material [b] (3) and the designability of the fiber-reinforced composite material. More preferably, it is 0.5 to 5 times, More preferably, it is 1 to 3 times.

Moreover, in the prepreg laminate 10, it is preferable that the thickness of the base material [b] is 0.1 to 3.0 times the thickness of the said prepreg structure [a1]. Thereby, it is possible to achieve both the impregnation into the base material [b] (3) and the designability of the fiber-reinforced composite material. More preferably, it is 0.2 to 2 times, More preferably, it is 0.5 to 1 time.

In addition, you may use two or more types of things of a different composition as prepreg laminated body prepreg [a]. The prepreg laminate can be designed according to the mechanical properties required of the fiber-reinforced composite material, the thickness of the fiber-reinforced composite material, and the like.

Since the prepreg laminate includes a structure in which two or more prepregs [a] in which a resin is impregnated into reinforcing fibers are continuously laminated, the resin is impregnated from the prepreg [a] to the base material [b] by the molding operation. Even after that, the void content is low, and as a result, it becomes a fiber-reinforced composite material having excellent mechanical properties such as strength. In addition, the material has a design surface with few pinholes.

On the other hand, in the case of a laminate in which the prepreg containing the resin is not laminated, and the prepreg and the base material not impregnated with the resin are alternately laminated, since the resin of the prepreg is impregnated into the base material and supplied, the fiber reinforced composite The fiber volume content of the material is high, and the void content is likely to be high. In addition, pinholes on the design surface may also occur.

Generally, a prepreg laminated body is obtained by laminating|stacking a prepreg according to the mechanical characteristic, thickness, etc. of the target fiber reinforced composite material. When a unidirectional prepreg is used, since anisotropy is expressed in the fiber-reinforced composite material, countermeasures such as pseudo-isotropic lamination can be taken.

Next, the fiber-reinforced composite material of the present invention will be described. All of these fiber-reinforced composite materials include a fiber-reinforced composite material layer [A] derived from a prepreg [a] impregnated with a resin into a reinforcing fiber, and a fiber-reinforced composite material layer derived from a substrate [b] that is not impregnated with a resin. [B] is included.

In the fiber-reinforced composite material layer [A] of the fiber-reinforced composite material of the present invention, the resin of the prepreg [a] is cured or solidified.

In the fiber-reinforced composite material layer [B] of the fiber-reinforced composite material of the present invention, a part of the resin in the prepreg [a] is impregnated with the base material [b], and the resin is cured or solidified therein.

In the fiber-reinforced composite material according to the present invention, when the average fiber volume content of the fiber-reinforced composite material layer [A] is VfA and the fiber volume content of the fiber-reinforced composite material layer [B] is VfB, VfA>VfB has a relationship it is preferable

Moreover, it is preferable from the point of designability of a fiber reinforced composite material that VfA is 55 % or more and VfB is 40 % or less.

In addition, in the fiber-reinforced composite material of the present invention, the resin impregnated with the fiber-reinforced composite material layer [B] is the resin impregnated in the prepreg [a]. Accordingly, during molding, air and volatile components contained in the prepreg [a] of the design surface move to the base material [b] together with the resin, thereby obtaining a fiber-reinforced composite material of an excellent design surface.

In the fiber-reinforced composite material of the present invention, the fiber volume content of the fiber-reinforced composite material layer [A] on both sides sandwiching the fiber-reinforced composite material layer [B] is preferably 55 to 90%. Thereby, the mechanical properties and designability of the fiber-reinforced composite material are excellent. Preferably it is 60 to 90%, More preferably, it is 70 to 80%. When the fiber volume content is small, the resin layer contained in the fiber-reinforced composite material layer [A] increases, and air and volatile components are difficult to transfer to the fiber-reinforced composite material layer [B], so that the designability of the fiber-reinforced composite material is improved. There are cases where this cannot be achieved sufficiently.

In addition, the fiber volume content of the fiber-reinforced composite material layer [B] is preferably 1 to 40% from the viewpoint of the impregnability of the resin in the prepreg. More preferably, it is 2 to 30%, and also 2 to 10%.

In the fiber-reinforced composite material of the present invention, if the void content of the fiber-reinforced composite material layer [B] is higher than the average of the void content of each layer of the fiber-reinforced composite material layer [A], the designability of the fiber-reinforced composite material can be improved. It is preferable that it is possible.

In addition, in the cut surface along the lamination direction of the prepreg [a] and the substrate [b], the voids of the fiber-reinforced composite material layer [B] are 80 to 100% distributed in the central portion of the fiber-reinforced composite material layer [B], It is preferable to have This is because the obtained fiber-reinforced composite material increases the adhesion between the layers.

Next, the manufacturing method of the fiber reinforced composite material of this invention is demonstrated. The manufacturing method of the fiber reinforced composite material of this invention has the process of heating and pressurizing the prepreg laminated body described above, and shaping|molding.

In the method for producing a fiber-reinforced composite material of the present invention, in the step of forming a prepreg laminate and the step of impregnating the resin contained in the prepreg [a] with the base material [b], and forming, the step of performing under reduced pressure It is preferable to further include. This is because the designability of the obtained fiber-reinforced composite material is excellent. The air and volatile components remaining in the vicinity of the design surface of the prepreg laminate are removed by the reduced pressure. As a result, a fiber-reinforced composite material having a more excellent design surface can be obtained. Under reduced pressure, it is the pressure which is -80 kPa or less in gauge pressure representation, Preferably it is -90 kPa or less, More preferably, it is -95 kPa or less.

In addition, in the method for producing a fiber-reinforced composite material of the present invention, when the resin contained in the prepreg [a] is impregnated with the substrate [b], air or volatile components contained in the resin move to the substrate [b] It is preferable to do Thereby, a fiber-reinforced composite material having an excellent design surface with few pinholes can be obtained.

As a manufacturing method of the fiber reinforced composite material of this invention, press molding using a shaping|molding die, vacuum bag shaping|molding, autoclave shaping|molding, etc. are mentioned, for example. Among these, the manufacturing method by autoclave molding is preferable at the point from which the fiber-reinforced composite material which has an outstanding design surface is obtained. 0.1 Mpa - 1.0 Mpa are preferable and, as for the shaping|molding pressure in autoclave shaping|molding, 0.3 Mpa - 0.6 Mpa are still more preferable at the point which can remove the pinhole of a design surface. The molding temperature in autoclave molding needs to be set according to the curing temperature of the resin used in the prepreg, but is usually in the range of 100°C to 200°C.

The design surface of the obtained fiber-reinforced composite material is subjected to a coating treatment such as clear coating or colored coating, and adhesion of a film. Since it is a fiber-reinforced composite material having a design surface with few pinholes, in the present invention, the effect is remarkably shown in the painting process.

Examples of the use of the fiber-reinforced composite material of the present invention include the following.

Personal computers, displays, OA equipment, mobile phones, portable information terminals, facsimiles, compact discs, portable MDs, portable radiocassettes, personal digital assistants (PDAs), video cameras, digital video cameras, optical devices, audio, Casings, trays, chassis, interior members, or parts of electrical and electronic devices such as air conditioners, lighting devices, entertainment products, toy products, and other household appliances.

Parts for civil engineering and building materials such as posts, panels, and reinforcing materials. Various members, various frames, various hinges, various arms, various axles, various wheel bearings, various beams, propeller shafts, wheels, gearboxes, suspension, accelerator or steering parts.

Hood, roof, door, fender, trunk lid, side panel, rear end panel, upper back panel, front body, under body, various pillars, various members, various frames, various beams, various supports, various rails, various hinges, etc. , shell or body parts.

Exterior parts such as bumpers, bumper beams, moles, undercovers, engine covers, baffles, spoilers, cow louvers, aero parts.

Interior parts such as instrument panels, seat frames, door trims, pillar trims, handles, and various modules.

Motor parts, CNG tank, gasoline tank, fuel pump, air intake, intake manifold, carburetor main body, carburetor spacer, various piping, various valves, etc. For fuel system, exhaust system, intake system, automobile, and two-wheeled vehicle structural parts.

Alternator terminal, alternator connector, IC regulator, potentiometer base for Light Deer, engine coolant joint, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, turbine vane, wiper motor related parts, distributor, start switch, Starter relay, window washer nozzle, air conditioner panel switch board, coil for fuel-related electromagnetic valve, battery tray, AT bracket, head lamp support, pedal housing, protector, horn terminal, step motor rotor, lamp socket, lamp reflector, lamp housing, Various parts for automobiles and two-wheeled vehicles such as brake piston, noise shield, spare tire cover, solenoid bobbin, engine oil filter, ignition case, scuff plate, fascia, etc.

Aircraft parts such as landing gear pods, winglets, spoilers, edges, ladders, elevators, failings, ribs, etc.

From the viewpoint of the mechanical properties, it is preferably used for interior and exterior of automobiles, electric/electronic device casings, bicycles, structural materials for sporting goods, aircraft interior materials, and transport boxes.

Example

Hereinafter, the present invention will be described more specifically by way of Examples.

In addition, this invention is not limited by these Examples.

<Prepreg [a] in which resin is impregnated with reinforcing fibers>

- The manufacturing method of the prepreg A which is a prepreg [a] is shown below.

[Epoxy Resin Composition]

In a kneading apparatus, 35 parts by mass of "jER" (registered trademark) 4007P (manufactured by Japan Epoxy Resin Co., Ltd.) and 35 parts by mass of triglycidyl-p-aminophenol ("Araldite" (registered trademark) MY0510 (Huntsman) -Advance Materials Co., Ltd.)) and 30 parts by mass of bisphenol F-type epoxy resin (“Epiclon” (registered trademark) 830 (manufactured by DIC Corporation)), 3 parts by mass of “Vinylek” (registered trademark) PVF -K (polyvinyl formal) (manufactured by Chisso Co., Ltd.)) was blended, and a thermoplastic resin (PVF-K) was dissolved in an epoxy resin. Thereafter, 5 parts by mass of dicyandiamide (curing agent, DICY-7, manufactured by Mitsubishi Chemical Co., Ltd.) as a curing agent, and DCMU99 (3-(3,4-dichlorophenyl)-1,1-dimethyl as a curing auxiliary agent) 3 parts by mass of urea and a curing accelerator (manufactured by Hodogaya Chemical Co., Ltd.) were kneaded to prepare an epoxy resin composition.

[Carbon Fiber A]

A copolymer containing 99 mol% of acrylonitrile and 1 mol% of itaconic acid was spun and fired to obtain carbon fibers having a total number of filaments of 3,000, specific gravity of 1.8, strand tensile strength of 3.5 GPa, and strand tensile modulus of 230 GPa. Next, the carbon fiber was electrolytically surface-treated with an amount of electricity of 3 coulombs per gram of carbon fiber using an aqueous solution of sulfuric acid having a concentration of 0.05 mol/L as an electrolyte. The carbon fiber to which this electrolytic surface treatment was given was continuously washed with water, and it dried in the heated air of the temperature of 150 degreeC, and obtained the carbon fiber used as a raw material. Then, “jER (registered trademark)” 825 (manufactured by Japan Epoxy Resin Co., Ltd.) was mixed with acetone to obtain an approximately 1% by mass acetone solution uniformly dissolved therein. Using this acetone solution, after applying to the carbon fiber surface-treated by the dipping method, heat treatment was performed at a temperature of 210 ° C. for 180 seconds to obtain a carbon fiber coated with a sizing agent. The adhesion amount of the sizing agent was adjusted so that it might become 0.5 mass parts with respect to 100 mass parts of surface-treated carbon fibers.

[Method for producing prepreg A]

The produced epoxy resin composition was apply|coated on the release paper using the knife coater, and the resin film of 66 g/m<2> was produced 2 sheets. On the other hand, a carbon fiber sheet A having a weight per unit area of 198 g/m 2 was produced in which the carbon fibers A were arranged in a twill cross in two directions in a sheet shape. The two resin films produced above are overlapped from both sides of the carbon fiber sheet A, and the resin is impregnated by heat and pressure, and the mass fraction of the matrix resin is 40.0%, the weight per unit area is 330 g / m 2 A prepreg was made.

<Substrate not impregnated with resin [b]>

The following base materials A, B and C used as the base material [b] were prepared.

Base A: "Toreka (registered trademark)" cross CO6151B (manufactured by Toray Co., Ltd.) (weight per unit area: 92 g/m2, thickness: 0.11 mm)

Base B: "Toreka (registered trademark)" cross CO6343B (manufactured by Toray Co., Ltd.)) (weight per unit area: 198 g/m2, thickness: 0.25 mm)

Base C: Surface mat, FC-30S (manufactured by Central Glass Fiber Co., Ltd.) (weight per unit area: 30 g/m2, thickness: 0.23 mm)

The method for measuring the fiber volume content of the prepreg [a], the substrate [b] or the fiber-reinforced composite material used in Examples, the method of measuring the void content of the fiber-reinforced composite material, and the void in the fiber-reinforced composite material layer [B] The distribution measuring method and the measuring method of the pinhole of the design surface are shown below. Unless otherwise specified, the production environment and evaluation of the prepreg laminate and the fiber-reinforced composite material of the Examples were performed in an atmosphere of a temperature of 25°C±2°C and a relative humidity of 50%.

(1) Fiber volume content of the fiber-reinforced composite material layer [A] and the fiber-reinforced composite material layer [B] in the fiber-reinforced composite material

From the fiber-reinforced composite material obtained in each Example, in the in-plane direction perpendicular to the lamination direction, a sample having a length of 20 mm x a width of 20 mm was cut out, the cross section was polished, and the cross section was examined under a laser microscope (KEYENCE VK- 9510), magnified 200 times or more, and took a picture so that it converges in the field of view of the second floor or more. From the same operation, 10 places were randomly selected for each layer, and the thickness of each layer was measured. The fiber volume content of each layer was calculated from the thickness of each layer, the weight per unit area of the fiber, and the fiber specific gravity. The average value of the fiber volume content of the fiber-reinforced composite material layer [A] of the sample and the average value of the fiber-reinforced composite material layer [B] were obtained. This was done for a total of 6 samples, and the average value of the 6 samples was taken as the fiber volume content.

(2) Void content of fiber-reinforced composite material

A cross section was photographed for a sample measuring 20 mm in length x 20 mm in width under the same conditions as (1). From the photograph of each layer, the binarization process of the void part and the part other than that was performed, and the void content rate of the fiber reinforced composite material was computed.

(3) Void distribution of fiber-reinforced composite material layer [B]

The cross section of the fiber-reinforced composite material obtained in Example (1) was photographed under the same conditions as in (1), and internal voids of the fiber-reinforced composite material were inspected. In the case where 80 to 100% of the void area of the entire cut surface was distributed in the central portion of the cut surface of the fiber-reinforced composite material layer [B], it was referred to as A, and when less than 80% of the voids were distributed in the central portion, it was referred to as B. Here, the central portion of the cut surface represents an area portion of 80% of the total area including the center of gravity in which the shape of the entire area of the cut surface is reduced to 80%.

(4) Pin hole on the design surface

The fiber-reinforced composite material produced in (1) was cut out to 100 mm long x 100 mm wide. The obtained sample was visually inspected for pinholes on the design surface. As a criterion for determination, when the number of pin holes was 10 or less, A ⁺ , 11 or more and 30 or less, A, and 31 or more, B.

(Example 1)

As shown in Table 1, using the prepreg A as the material of the prepreg [a] and using the substrate A as the substrate [b], from the design surface, the prepreg A, the substrate A, the first prepreg A and the second Four layers were laminated in order of the prepreg A, and the prepreg laminated body was produced. The laminated structure in which the prepreg A on the design surface includes the prepreg structure [a2], the first prepreg A, and the second prepreg A in the present invention corresponds to the prepreg [a1] structure.

Using the obtained prepreg laminate, it was molded in an autoclave at a temperature of 130° C. for 2 hours under a pressure of 0.5 MPa at a temperature increase rate of 1.6° C./min to produce a fiber-reinforced composite material. Table 1 shows the fiber volume content of the fiber-reinforced composite material, the void content of the fiber-reinforced composite material, the void distribution of the fiber-reinforced composite material layer [B], and the measurement results of the design surface pinholes.

(Examples 2 and 3)

Except having changed the material of the base material [b] to the thing shown in Table 1, it carried out similarly to Example 1, and produced the prepreg laminated body. Table 1 shows the measurement results of the produced prepreg laminate.

(Examples 4 to 6)

Using the prepreg A as the material of the prepreg [a] and using the substrate A as the substrate [b], from the design surface, in the order as shown in Table 1, a prepreg composed of a plurality of prepregs A and the substrate A A leg laminate was produced. Table 1 shows the measurement results.

(Comparative Examples 1 to 4)

Using the prepreg A as the material of the prepreg [a], and using the substrate B or the substrate C as the substrate [b], in the order as shown in Table 1 from the design surface, a plurality of prepregs A and substrate B or A prepreg laminate composed of C was produced. In Comparative Example 1, the base [b] not impregnated with the resin was not used. Table 2 shows the measurement results.

[Table 1A]

[Table 1B]

[Table 2A]

[Table 2B]

By contrast of Examples 1 to 6 and Comparative Examples 1 to 4, the fiber-reinforced composite material of the present invention has an excellent design surface. This is because when the resin from the prepreg is impregnated with the resin-unimpregnated substrate, air and volatile components that cause pinholes on the design surface are also transferred to the resin-unimpregnated substrate. Furthermore, since the fiber-reinforced composite material of the present invention has a low void content, it can be expected that the mechanical properties are also excellent.

According to the present invention, since a fiber-reinforced composite material having an excellent design surface is obtained, sporting goods such as tennis rackets and golf shafts, automobile exterior materials such as bumpers and doors, automobile structural materials such as chassis and front side members, or steering It can be widely deployed and useful for automobile interior materials such as meter visors, aircraft structural members, windmill blades, or computer applications such as IC trays and casings (housings) of notebook computers.

1: design surface
2: group of prepreg [a]
2a1, 2a2, 2a3, 2b1 and 2b2: prepreg [a]
3: description [b]
10: prepreg laminate

Claims (17)

A prepreg [a] in which the resin is impregnated into the reinforcing fibers and a base [b] in which the resin is not impregnated,
It has a structure in which at least two prepregs [a] are continuously stacked among the prepregs [a],
A fiber-reinforced composite material using a prepreg laminate including a structure in which both sides of the substrate [b] are sandwiched with the prepreg [a],
If the fiber volume content of the fiber-reinforced composite material layer [A] derived from the prepreg [a] is VfA, and the fiber volume content of the fiber-reinforced composite material layer [B] derived from the base [b] is VfB, VfA Fiber-reinforced composites, with a relationship of >VfB. The fiber-reinforced composite material according to claim 1, wherein the thickness of the substrate [b] is 0.1 to 1.5 mm. The fiber-reinforced composite material according to claim 1 or 2, wherein the thickness of the prepreg structure [a1] defined below is 0.2 to 9 times the thickness of one sheet of the prepreg [a2] defined below.
Prepreg structure [a1]: A structure comprising the prepreg [a] laminated on one side of the base material [b], in which two or more sheets of the prepreg [a] are successively laminated
Prepreg [a2]: A prepreg [a] laminated on the other side of the substrate [b] (however, when the prepreg [a] is laminated, a laminate of the prepreg [a]) The fiber-reinforced composite material according to claim 1 or 2, wherein the thickness of the substrate [b] is 0.1 to 3.0 times the thickness of the prepreg structure [a1] defined below.
Prepreg structure [a1]: A structure comprising the prepreg [a] laminated on one side of the base material [b], in which two or more sheets of the prepreg [a] are successively laminated The fiber-reinforced composite material according to claim 1 or 2, wherein at least one surface of the prepreg laminate is a design surface, and the substrate [b] is laminated on the second or third layer from the design surface side. The prepreg according to claim 1 or 2, wherein at least one surface of the prepreg laminate is a design surface, and the prepreg [a], the base material [b] and two or more prepregs are sequentially from the outermost layer on the design surface side. A fiber-reinforced composite material having a structure in which [a] is continuously laminated. The fiber-reinforced composite material according to claim 1 or 2, wherein the base material [b] has a weight per unit area of 5 to 100 g/m 2 . The fiber-reinforced composite material according to claim 1 or 2, wherein the substrate [b] contains carbon fibers or glass fibers, and the fibers are discontinuous. The fiber-reinforced composite material according to claim 1 or 2, wherein the fiber-reinforced composite material layer [B] contains a resin, and the impregnated resin is a resin impregnated in the prepreg [a]. The fiber-reinforced composite material according to claim 1 or 2, wherein the fiber volume content of the fiber-reinforced composite material layer [B] is 40% or less. The fiber-reinforced composite material according to claim 1 or 2, wherein the fiber-reinforced composite material layer [A] present on both sides of the fiber-reinforced composite material layer [B] has a fiber volume content of 55% or more, respectively. The fiber-reinforced composite material according to claim 1 or 2, wherein the void content of the fiber-reinforced composite material layer [B] is higher than that of the fiber-reinforced composite material layer [A]. The method according to claim 1 or 2, wherein the voids contained in the fiber-reinforced composite material layer [B] are 80 to 100% distributed in the central portion of the cut surface in the cross section along the lamination direction of the prepreg laminate, which is a fiber-reinforced composite material. A prepreg [a] in which the resin is impregnated into the reinforcing fibers and a base [b] in which the resin is not impregnated,
It has a structure in which at least two prepregs [a] are continuously stacked among the prepregs [a],
A method for producing a fiber-reinforced composite material comprising a step of heating and pressing a prepreg laminate including a structure in which both sides of the substrate [b] are sandwiched with the prepreg [a], and molding,
If the fiber volume content of the fiber-reinforced composite material layer [A] derived from the prepreg [a] is VfA, and the fiber volume content of the fiber-reinforced composite material layer [B] derived from the base [b] is VfB, VfA A method for producing a fiber-reinforced composite material with a relationship of >VfB. The method for manufacturing a fiber-reinforced composite material according to claim 14, further comprising a step of performing the molding at a pressure of -80 kPa or less (gauge pressure). The method for producing a fiber-reinforced composite material according to claim 14, wherein in the heating and pressurizing step, the resin contained in the prepreg [a] is impregnated into the base material [b]. delete

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